Answer: D) will play.
Explanation: a predicate is the part of a sentence or clause containing a verb and stating something about the subject. The simple predicate is the main verb in the predicate that tells what the subject does, it must include the auxiliary verbs as well. In the given sentence, the simple predicate is "will play" because "play" is the main verb and "will" is the helping verb. So the correct answer is option D.